Site vanished after 5.1 update

Running a project management system for my client’s work, where they can log in for discussions, find files, approve tasks etc, via the ‘WP-Project’ plugin.

That directory is set aside specifically for that purpose, project management.

The site updated to 5.1, an auto-update.

I go to login today, all I have is a white screen and the letters “pm”.

Have written to the plugin people, see if they can help, also asking here if there’s anything I can to do prevent these update-related disasters?

Yes disaster is the correct word when a client cannot login and emails me that his access to the site is gone and is there a problem we need to talk about? I probably won’t lose this contract, as this client has worked with me before but if a new client? Yes, disaster is the word.

I’ve run a manual restore to the 23rd, so the site is back up now, however I’m told it will auto-self destruct again. I though this version was supposed to NOT do the self-destruct thing?

So what am I supposed to do now, in this world of compulsory and destructive updates?

Thanks,

A.

The page I need help with: [log in to see the link]